Insulator bracket



R. J. BERTLING INSULATOR BRACKET June 28, 1960' Filed April 4. 1956 INVEN TOR. Ronald J Berti" 4' INSULATOR' BRACKET Ronald J. Bertling,.Sjouth Milwaukee, Wis, assign-or. to McGraw-Edison Company, a corporation of Delaware Filed Apr; 4', 1956, Ser; No. 576,150-

2 A Claims. (Cl. 248-67 .7)

Therpresent invention relatesto insulatorv brackets, or so-calledsecondary brackets, used in, connection Wltil supportingv insulators for. power. and light conductors. Such devices, ordinarily. comprise. a base member provided with, supporting. elements projecting therefrom, which supporting,.elementsare designed to receive a rodl onthe: likerupon which the insulators are. mounted.v

As..heretofore.constructed, it has been common prac; tice-inthe art to, provide sheetmetal'. constructions including support arms :being formedofsheet metal, and. it.

is ,welLknown to provideracks of forged members has;-

ing a substantially circular cross section intermediatethe ends thereof. Howevenas far as can be determined,

there has been little. consideration to providing a struc= ture having relativelyhigh strengthsin. cantilever and. at thesa-me time-beingrelatively inexpensive to manufacture from commercially available stock...

It is therefore amongthe objects oftherpresent invention to provide an improved insulator support offering the strengthpf forged members, anda..which::may be manufactured .economicallyof oval bar. stock. or the like, which stock is positioned relative to a base member portion in a manner which will permit optimum resistance to cantilever forces appliedv to thefree end thereof. .The use of commercially available.oval..stoc k.permits.- simpli'. fied upsetting procedures .forproviding mounting'means, and in addition, provides a relatively smooth surface' for sagging and stringing operations.

In the drawing:

Fig. 1 is a fragmentary side elevational view of a secondary or service rack embodying my invention.

Fig. 2 is a partial sectional view on line 2-2 of Fig. 1.

Fig. 3 is a sectional view on line 3-3 of Fig. 1.

Fig. 4 is an elevational view of a support arm removed from the base member, and shown prior to positioning and riveting in place.

Fig. 5 is a cross sectional view on line 55 of Fig. 4.

Fig. 6 is a cross sectional view on line 66 of Fig. 4.

To illustrate a preferred embodiment of the present invention, an elongated base member 10 of channeled cross section is provided, as shown more specifically in Fig. 3, having side flanges 11 and 12, which permit the body portion of the base member to extend outwardly relative to the support to which it may be connected. The base member may be connected to the wall of the building or to a pole or other suitable support by means of screws, bolts, or the like, and may be provided with the apertures 13, '1'4 and 15 for this purpose.

The body portion of the base member is also provided with longitudinally spaced apart apertures 16 in which are received the support members for holding an insulator supporting rod.

The outwardly extending support members 20 are preferably provided from commercially available bar stock having an oval cross section (see Fig. 5). In manufacturing the device, a suitable length of bar stock having an oval cross section, is precut and flattened at an end portion to provide the relatively flat surfaces 21 and .awn

e lC

22,,whichportion is. intended to be positioned outwardly" relative to. the base member 10. The flattened portion is:

either drilled on stamped to provide an eye- 23 (seeFigi 4) for slidably' receiving the headed through rod 24, as:

shown in Fig. 1.

It is. a part ofthe present invention toprovide the support members 20 withi the eye 23 in the position shown in orderto permitthe-axis of the through rod24-to be substantially nor-malto the pl-ane passing through the' major axis of the oval cross section of -the support member 20. It will be apparent that such constructionprovides the greatest portion of metal in'the-direction of resist-anceto cantilever forcesexerted laterally relative ber 20 is the preforming of the lower extending'member 26 to approximate its shape-as shown in Fig. 4; This canbe done in conventional .gripper dies which are rnov-' able'laterallyrelative to one another (notshown'). The

next step in fabrication is to place the oval stock' within a pair of conventional gripping dies-(not shown). whichhave a portion recessed 'at the'to'pv for forming the'outwardly extendingoppiosed embossments or lugs- 2'5'. The opposed embossments, together with themajoraxis of the oval. cross section,: provide a stable surface'for abutting supporting engagement with the" topof the'bas'e' member 10. That is, although the aforesaid-cantilever forces in the direction offrotation about thelongitudinalaxis of theibase member are:proportionally greater-than other forces exerted onLth'e assembly," his 1 not" to be for:

gotten that relative mounting heights aboveground level of-theseassemblieszcause additional shear forces-"to be imposed uponv a respective support member20 in all directions about its base: Thus'a'substantial stable-surface is a necessity for .eflicient stren'gth characteristics.'=

To continue with the forming of the supporr member; I

after placement of the oval stock in the gripper dies (not shown) is assured, the dies are closed and a punch having a chamber of the cross section of the lower extending member 26 (see Figs. 4 and 6) is moved endwise towards the preformed member 26, heading the member to the final cross section of the portion 26 and simultaneously providing the embossments 25. This operation is generally known as upset forging.

After the piece has been formed to the configuration shown in Figs. 4, 5 and 6, it is inserted in the base member 10 in the relative position shown in Figs. 1, 2 and 3 with the major axis of the oval cross section being substantially normal to the longitudinal axis of the base member. The entire assembly, with the various support members 20 being placed therein, is either positioned in a jig as assembled, or is moved in a riveting die intermittently as each riveting operation is completed. The riveting operation is relatively simple and is provided by means of a punch forming the indentation 30* (see Fig. 3) which forces metal radially outwardly to provide the riveting flange 31 in tight clamping engagement with the base member 10.

After the support members 20 have been positioned in the base member 10, the through rod 24 is positioned in the axially aligned openings '23 of each support memher with the appropriate insulator spool 35 being mounted thereon. The through rod 24 is preferably headed at one end and may be held in place by means of cotter pins (not shown) to prevent axial endwise movement thereof.

'It will be apparent that the manner of mounting the Patented June 28, 1960 t 3 support member to the base member should be considered in its broadest aspect. That is, it is within the scope of the present invention to projection weld or otherwise wel-d the support member to the base, And,

in fact, it is conceivable that oyal cross section tubing bers may be fabricated from sintered metal or may becast to shape if so desired.

It will be obvious that the provision of the relatively flat opposed surfaces 21 and 22 is preferably, inasmuch as the surface 21 provides a relatively extended portion for laterally supporting the spool-type insulator 35, it is possible to fabricate the support members without flattenting the ends if such is found to be desirable.

It will be especially apparent that the oval cross section support members provide still another advantage in their relatively broad surface. That is, when positioned as shown with the major axis substantially normal to the longitudinal axis of the base member, the smooth oval surface of the support members will provide a less abrasive resistance during sagging or stringing conductors prior to fastening to the insulators 35. That is, in actual practice, the racks are generally mounted as viewed in Fig. 1 on a pole or wall with the through pin 24 being substantially vertical. Conductors are threaded through each rack, and the support members act totemporarilysupport the conductor during the sagging or stringing operation, and if they are provided with too small a surface they will tend to cause the conductor to bend sharply, and otherwise abraid the conductor during movement thereof.

Another factor in using oval stock rather than stock of round cross section, is that during the flattening operation, which provides surfaces 21 and 22, a round section tends to grow in an endwise direction. Obviously, such growth would materially effect the strength of the arm, and would require additional means for resisting the same in order to maintain uniformity in length for axial alignment of the openings for receiving the through pin. It has been found that flattening has no effect on the lengthwise dimension of the oval cross section stock.

From the foregoing, it will be apparent that an improved insulator bracket has been provided which takes full advantage of economical manufacture and increased channeled base member formed from sheet metal and having a plurality of spaced apart apertures therein, a plurality of support arms fixedly secured to said bracket and extending outwardly therefrom, each of said arms being forged from stock of oval cross-section with the major axis of said cross-section being substantially normal to the longitudinal axis of said base member, each of said arms further being symmetrically shaped about.

a plane through its longitudinal axis normal to the iongitudinal axis of the base member whereby when reversed 2. A structure as set forth in claim 1 wherein the I outer end of each of said arms is flattened on opposed sides for a distance inwardly from said outer end.

References Cited in the file of this patent UNITED STATES PATENTS 1,779,489 Peirce Oct. 28, 1930 1,822,037 Kerschner Sept. 8, 1931 1,866,104 Heim f July 5, 1932' 1,897,385 Fassinger Feb. 14, 1935 2,008,744 Brady July 23, 1935 

